The long range objective of this research is to understand the distribution of positional information underlying embryonic axon growth and synaptogenesis. The work is based on earlier studies which showed that following embryonic eye translocations optic nerve fibers establish highly directed growth trajectories in regions of the CNS they would normally never penetrate. Proposed experiments will use autoradiography, horseradish peroxidase histochemistry, electrophysiology, and ultrastructural techniques to study the growth and termination pattern of optic tracts following a variety of eye transplantations and surgical manipulations of the neural tube. These experiments are designed to: 1) identify parameters which have a consistent effect on optic tract growth and termination; 2) determine whether any of these parameters are present only in the embryo; 3) fully explore our discovery of eye-specific bands of terminals in tecta innervated by two complete retinas, 4) examine the development of central visual pathways in the absence of retinal input. This research will be conducted on anuran (Rana pipiens) material. However, the results of this work should provide insight into basic principles of vertebrate neural pathway development which may then be applied to the prevention and treatment of human neurological disorders.